Cellular telephones typically include either a retractable, whip-type antenna, or a fixed or retractable helical antenna, or a combination of two or more of these types. In any case, there must generally be some protrusion from the typically rectangular case of the phone in order to attain acceptably high antenna gain and, thus, good quality reception. The protrusion makes the telephone less convenient to carry, for example, in a clothes pocket, and is prone to breakage.
FIG. 1 is a schematic illustration of a type of feedthrough-fed antenna known in the art as an "Inverted-F" antenna 20. The antenna comprises a ground plane 22 and a conducting plate 24, fixed in a generally parallel, mutually-spaced relation to the ground plane. Plate 24 is coupled to ground plane 22 by a ground connection 26 at one end of the plate. A 50 ohm feed-through 28 couples plate 24 to a suitable transmitter and/or receiver circuit (not shown in the figures), as is known in the art.